1. Field of the Invention
The present invention relates to a one-way spring coupler through which rotation is transmitted from a drive member to a driven member but rotation is not reversibly transmitted.
2. Description of the Prior Art
A conventional spring coupler is disclosed in U.S. Pat. No. 4,651,854. In this spring coupler, upon rotation of a drive member in one direction, the drive member is brought into engagement with an end portion or a tang of a coil spring resulting in a reduction of the radius thereof Thus, the frictional contact between the coil spring and an inner surface of a casing is released so that the rotation of the drive member is transmitted to a driven member.
The drive member includes a main portion as a dial at which the rotation is applied and a core portion through which rotation is transmitted to a core portion of the driven member. For constituting the drive member; the main portion and the core portion are formed integrally with each other in a mold during the insert-formation of the core portion. For constituting the driven member, the main portion and the core portion each, of which is made with a sintered metal are, coupled with each other. In order to assure the connection therebetween, copper-infiltration is employed.
However, the conventional spring coupler has drawbacks because considerable time and cumbersome operations are required to constitute the drive member and/or the driven member.